Reaction injection molding ("RIM") is a well-known method for manufacture of molded polyurethane parts. In the RIM method, an isocyanate component is reacted with a polyol component that is filled with Barium Sulfate or other filler materials to produce a filled polyurethane elastomer. The filled polyurethanes may be used in numerous applications, including acoustical insulation for automotive vehicles. When used as acoustical insulation, the filled polyurethanes should have a specific gravity of at least about 1.5.
A long standing problem in achieving filled polyurethanes which have a specitic gravity of at least about 1.5 is that a polyol filled with a sufficient amount of filler to yield this specific gravity has a viscosity of more than 100,000 centipoise ("cps"). This renders use of the filled polyol impractical or impossible in RIM methods.
A need therefore exists for filled polyols which can be employed in RIM methods and which provide filled polyurethanes which have a specific gravity of at least about 1.5 and which have a viscosity less than about 100,000 centipoise at 25.degree. C.